The present invention relates to a new and improved nail protection preparation intended to strengthen, particularly by hardening, living finger and toe nails, and is of the type comprising two separate components, the first of which contains a polymerizable compound and the second of which contains a compound acting as a polymerization catalyst. The invention further pertains to a method of using the novel preparation for the protection of living nails.
It is well known that living nails, which consist of keratin, tend to grow brittle when subjected to the action of organic solvents of the type contained in nail polishes or polish removers, and in washing agents and detergents and other cleaning agents. This brittleness causes the nails to splinter or tear, even when subjected to modest or slight mechanical loads.
A drawback of heretofore known nail protection preparations is that they are effective only for a relatively short period of time, because the protective film is soluble in water, and therefore, very quickly is entirely or partly washed away. Moreover, with some of the conventionally used nail protection preparations--those which are less soluble and cause the formation of a dense protective coat--there exists the risk of asphyxiating the nails unless great care is exercised in applying the protective preparation in a manner which precludes the protective coat from extending to the nail roots. Thus, for instance, in U.S. Pat. No. 3,349,000 there is disclosed a process for the treatment of human nails and hair, wherein the nails or hair are treated with a liquid preparation containing dimethylol thiourea in a quantity of 1 to 15 percent-by-weight based upon the total weight of the product, and about 0.2 to 2 percent-by-weight of a physiologically harmless acid compound selected from the group consisting of phosphoric acid, lactic acid, citric acid, acetic acid, glycerine phosphoric acid and the acid salts of these compounds and a liquid diluent.
In U.S. Pat. No. 3,725,525 there is described a procedure for fortifying living human nails and hair, wherein nails or hair are treated with an effective quantity of dimethylol alkyleneurea or dimethylol alkylene thiourea of the formula ##STR1## wherein R is an alkylene group containing 2 to 5 carbon atoms, and X is CO or CS. While the results attained with these prior art procedures were better than those obtained with earlier preparations, particularly as regards the elasticity of the treated nails, these methods have failed to achieve a protective effect of long lasting durations, and notably did not harden the nails. In addition, the concentration of urea derivatives of the methylol groups had to be kept very low, in order to reduce to a minimum the quantity of formaldehyde released during the reaction, since formaldehyde is notorious for causing skin irritation, especially allergies.
With the aim of eliminating the noxious effects of free formaldehyde entirely or at least almost completely, U.S. Pat. No. 3,773,056 teaches compositions and procedures for the treatment of degraded hair which use less easily decomposable urea and thiourea derivatives, such as carbamates, guanidines, succinimides, sulphinamides, adipinamides or hydantoins, in order to produce a reaction with organic acids or corresponding acid salts by applying these acids to the hair prior, during or after treatment with urea or thiourea derivatives. This remedy succeeds simply in fortifying or strenghtening human hair inasmuch as it improves its elasticity, but it does not in any way act as a hardener.